Fujitsu Corporation

Kabushiki Kaisha Toshiba

Other

Toshiba Storage Device Corporation

Tomoyoshi Yamada

Keiji Aruga

Shinji Koganezawa

Yasumasa Kuroba

Yoshifumi Mizoshita

Takao Sugawara

Hiroyuki Mase

Masaru Matsumoto

Toru Kouhei

Kazuhiko Takaishi

Yukihiro Uematsu

Masao Tsunekewa

Hiroyuki Suzuki

Takeyori Hara

Tetsuya Suzuki

Takahiro Imamura

Tsugito Maruyama

Susumu Hasegawa

Toru Kohei

Masanori Fukushi

Hiroshi Takekawa

Kei Funabashi

Takahisa Ueno

Tadayoshi Noguchi

Junichi Inoue

Ryuma Sakamoto

Hisashi Nakano

Nobuyuki Suzuki

Shuichi Hashimoto

Sumio Kuroda

Hiroshi Maeda

Masaharu Sugimoto

Mitsuo Kamimura

Hiroyuki Iwahara

Mitsuaki Yoshida

Yuji Sasaki

Masao Tsunekawa

Toshiyuki Hachiya

Norihiko Suzuki

Masaharu Sakata

Tohru Kouhei

Takuya Kobayashi

According to one embodiment, at demodulation of an A-phase burst pattern and a B-phase burst pattern arranged in a down-track direction so as to be different from each other in phase in a cross-track direction, the demodulated position of a magnetic head is calculated based on a sin component and a cos component in the A-phase burst pattern and a sin component and a cos component in the B-phase burst pattern.

Head position demodulation method and magnetic disk device

A magnetic disk device according to an embodiment includes a head and a disk with a recording surface, the head including a reader configured to perform data reading, and a writer configured to write data. A method of correcting a read/write offset, according to the embodiment, is applied to the above magnetic disk device. This method includes reconstructing position data read by the reader, using a spline function, and correcting a read/write offset due to the distance between the writer and the reader, using the reconstructed position data.

Magnetic disk device and method for read/write offset error correction

According to one embodiment, in a method for servo demodulation, a first demodulated signal and a second demodulated signal, which are calculated from amplitude values of burst signal patterns of a first area and a second area, are generated in order to generate a position error signal of a reader, based on a servo pattern read from a disk by the reader. Further, in the method for servo demodulation, a square-root of sum of squares of the first and the second demodulated signals is calculated, and an optimal compensation coefficient of a linearity correction function to be used in linearity compensation of the position error signal is calculated based on a maximum value and a minimum value of the square-root of sum of squares.

Method for servo demodulation and disk storage apparatus

According to an embodiment, a disk storage apparatus includes a disk with a servo pattern recorded thereon and a processor. The processor offsets a reader in a cross-track direction on the disk and performs a discrete Fourier transform (DFT) operation on an amplitude sequence of readback signals with respect to the cross-track direction. The processor calculates an optimal correction coefficient for a linearity correction function used for a linearity correction of a position error signal based on a result of the DFT operation.

Disk storage apparatus and method for servo demodulation

A master-disk producing device produces a master disk with master-disk identification information added. A disk producing device produces a first disk with the master-disk identification information added, using the master disk with the master-disk identification information added. A first disk device obtains, after the first disk with the master-disk identification information added is mounted, first correction information from a correction-information storing device based on the master-disk identification information of the first disk.

Disk-device correcting system, information managing device, master-disk producing device, and master-disk producing method

An actuator supports a head at one end of a rotatably supported shaft unit and supports a coil of a voice coil motor at the other end, and moves the head to an arbitrary track position of a recording medium. A sensor, attached to a coil support unit of the actuator, detects the coil vibration and outputs a vibration detected signal. A control unit controls the actuator to reduce a head position error signal based on the vibration detected signal of the sensor in time of seek and in time of settling of moving the head to a target track position on the medium through drive of the actuator and drawing the same. The vibration detected signal of the sensor includes bending vibration component of the coil and the twisting vibration component of the coil when the actuator is driven.

Storage apparatus and control method for detecting vibration produced during seeking

A storing unit stores first correction information for correcting a distortion synchronized with a rotation frequency of servo information of a first disk. A control unit controls positioning of a head on a target track by correcting the servo information of the first disk with the first correction information. Measurement information used for measuring the first correction information is calculated based on second correction information for the servo information in other disk apparatus including a second disk on which the servo information is formed using a common master medium with the first disk.

Disk apparatus, information processing system, and information providing apparatus

A plurality of HDDs--connected around a hostcan be made to directly communicate with each other. For example, an HDD-makes another HDD to perform long distance seek using this communication line and measures the influence of vibration caused at that time. The measurement result is formed into a transfer function indicating the position change of the head of the relevant HDD against the operation of another HDD. An HDD is actually driven by a current value obtained by correcting the normal driving current of the driving motor of the head by the transfer function.

Disk device with bi-directional communication function

A ramp member is supported on a flying slider in a load/unload mechanism of a recording medium drive. The flying slider receives a lift at its air bearing surface based on airflow generated along the moving recording medium. The flying slider flies above the recording medium. The flying height of the flying slider can be controlled with a higher accuracy in the same manner as a flying head slider utilized to read and write data from and into the recording medium. The slope of the ramp member on the flying slider can accordingly be kept at a predetermined level above the recording medium with a higher accuracy. Even if the extent of the slope is reduced, the load bar is allowed to reliably contact the slope. This leads to expansion of the data zone on the recording medium.

Ramp member assembly including flying slider in recording disk drive

Disclosed herein is a head actuator for a head provided so as to accessible to a disk-shaped recording medium rotating above a base. The head actuator includes a main actuator driven so as to rotate above the base, and a microactuator driven so as to swing relative to the main actuator. The head is mounted on the microactuator. The main actuator and the microactuator are controlled so that the head is moved in a substantially radial direction of the recording medium and positioned over a desired track of the recording medium. A primary resonant frequency of mechanical characteristics of the main actuator is set to 100 Hz or higher. This setting may be achieved by increasing a preload in a ball bearing of the main actuator, for example, to thereby increase the rigidity of a nonlinear spring of the ball bearing. In the case that a disturbance acts on the main actuator, the above setting allows a reduction in displacement of the microactuator required for positioning of the head over the desired track.

Head actuator

A method of STW (servo track write) for improving the quality of the servo tracks by suppressing the misalignment of the write start position caused by the asynchronous continuous vibration of a disk drive is disclosed. The disk drive includes a spindle motor, a disk medium, a write/read head and a head moving mechanism for carrying out the sector servo operation. The STW method comprises the steps of detecting the continuous vibration asynchronous with the rotational frequency of the spindle motor, detecting the phase of the asynchronous continuous vibration detected, determining the write start sector of each servo track based on the detected phase of the asynchronous continuous vibration, determining the write start time of each servo track in accordance with the clock signal, and moving the head onto the servo track where the head positioning information is written, by the head moving mechanism and writing the information in the servo track based on the write start time.

Method of writing servo tracks for disk file apparatus using write start or stop sectors

This invention relates to a head position control method for a disk device that uses a disk medium whose tracks have been formatted externally, and a disk device that effectively uses the range of motion of an actuator. In a disk device that has a disk medium, a head, an actuator, a control circuit, there is a conversion mechanism that sets a data area in the writing range of the disk that corresponds to the range of motion of the actuator, and converts a logical address to a physical address in the data area. This invention makes it possible to set a storage capacity that makes maximum use of the range of motion of the actuator for any device, even when there is a position offset in the range of motion of the actuator.

Head position control method for a disk device and the disk device

A head carriage assembly drive system has a head carriage assembly having a head, a head carriage for moving the head in a radial direction of a rotating disk, a first drive unit for generating the power to rotate the head carriage and a second drive unit having a torque constant smaller than the torque constant of the first drive unit. Mainly the first drive unit is operated in a low-frequency band and mainly the second drive unit is operated in a high-frequency band, thereby reducing overall power consumption during tracking.

Head carriage assembly drive system and disk drive

An actuator includes a shear-type piezoelectric element of predetermined thickness and an opposed electrode formed on two electrodes in spaced relationship on a base member. The opposed electrode is displaced in accordance with the direction of polarization of the shear-type piezoelectric element upon applying a voltage between the two electrodes. The opposed electrode thus constitutes an operating section of the actuator. The actuator can be incorporated as a part of the head actuator to constitute a head-positioning mechanism capable of displacing the head by a minuscule distance independently of the operation of the head actuator.

Actuator using piezoelectric element and head-positioning mechanism using the actuator

An object of the present invention is to implement head position control in a disk drive for the case in which a disk is assembled into the disk drive after a precise track is recorded onto it using an external apparatus, which is capable of high-speed access even if there is eccentricity between a track defined by servo information and the center of rotation of the track. Two phase servo bursts consisting of servo information are recorded onto each of the servo information regions of a disk surface, in mutual alternation, the strength ratio between signals detected from these two phase servo bursts being used to determine to which side the head is displaced. By performing control so that this strength ratio is a prescribed value at each angular position, control is achieved so that the head moves along a circular path of rotation, even if there is eccentricity in the servo circular path defined by the recorded servo information with respect to the center of rotation.

Head position control for a disk drive which performs recording about the rotational center even if the recorded servo information is eccentric

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Kawasaki, Japan

Tomoyoshi Yamada